Micrometer.



H.- SPAHN.

MIGROMETER.

APPLIOATIoN FILED 1330.19, 190s.

939,562. y Patented Nov.`9, 1909.

lANDREW. s. Gamm Px-lmoufHoGRAPMERS. WASHINGTON. D. c.

HENRY SPAI-IN, OF CHICAGO, ILLINOIS.

IVIICROMETER.

Specification of Letters Patent.

Patented Nov. 9, 1909.

Application led December 19, 1908. Serial No. 468,409.

To all whom it may concern:

Be it known that I, HENRY SPAHN, citizen of the United States, residingat Chicago, in the county of Cook and State of Illinois, have inventedcertain new and useful Improvements in Micrometers; and I-do herebydeclare the followino to be a full, clear, and exact description of theinvention', such as will enable others skilled in the art to which itappert-ains to make and use the same.

This invention relates to a novel construction in a micrometer and hasfor its object to provide means whereby a depth gage of any well-knownpattern may be converted into a micrometer adapted for all outsidemeasurements of bodies which are within certain limits and also theinner dimensions of all openings and recesses, and consists in thefeatures of construction and combinations of parts hereinafter fullydescribed and claimed.

In the accompanying drawings illustrating my invention: Figure 1 is aview in side elevation and partly in section of a micrometer constructedin accordance with my invention. Fig. 2 'is a view in side elevation ofa modied form of construction of the same. Fig. 3- is adetail section onthe line 3 3 of Fig. l

At the present time the machinist is obliged to provide himself withquite a largeV variety of sizes and styles of micrometers in order toenable him to measure various diameters and thicknesses of bodies,various sizes of openings, and various depths of recesses. For example,one micrometer will measure up to one inch diameter, another from oneinch to two inches, and so on. The same is true of inside micrometers.The depth gage covers a wider range of measurements. These instrumentsare very expensive and a complete set necessitates a large investment.

The object of my present invention is to provide an instrument, orrather an attachment to a depth gage whereby the latter may be easilyconverted into a micrometer for measuring either small or largediameters or thicknesses up to certain maximum dimensions and insidediameters or dimensions of openings between certain maximum and minimumlimits, thereby obviating the necessity of purchasing a large number ofinstruments to cover a dimensions.

The depth-gage is well-known and consists of a base or foot 1 lowerface. The gage rod Q passes centrally through the base 1 and is disposedperpendicularly to the plane lower face thereof. The said rod Q isprovided at intervals of one-half inch with annular grooves 3- engagedin a well-known manner to hold said rod against longitudinal movementrelatively to the engaging member. The latter has threaded engagementwith a hollow cylindrical standard disposed on the center of the upperface of the base or foot 1 and serves when turned to impart movement tosaid rod relatively to the latter. A nut 4lcontrols the engagingrelation between said rod and the engaging member and when turned in onedirection permits the rod to be moved longitudinally relatively thereto.

- I have illustrated the Brown and Sharpe depth gage and the abovedescription refers particularly to this type which 1s probably mostgenerally used.

In the upper face ofthe base or foot 1 on either side of the middleportion thereof is a recess 5 My attachment comprises a member 6provided in one end with a rectangular recess 7 in which one end of thebase or foot 1 is received, the latter being secured by means of theset-screws 8 entering the recess 5 therein. At its other end the saidmember 6- terminates in a cylindrical shank 9 provided at diametricallyopposite points with conical recesses l0 The shank 9 enters thecylindrical recess 1l in the arm 12 of a member 13 and is securedtherein by means of a set-screw 14- having a conical end entering one ofsaid recesses l0 and serving to secure said members 6 and l3 againstrelative movement in all directions.

The y arm l5 of the member 13 is disposed perpendicularly to the arm 12thereof and its free end portion is cylindrical, a portion thereof beingcut away to provide a fiat face 16 extending almost the entire length ofthe said free end portion.

lThe position of the recesses l0 relacertain range of having a planetively to the walls of the recess -7- and the position of the set-screw-ltrelat-ively to the arms of the member M18- is such that they coactwith each other to maintain the said arms of said member -13- and therod -2- of the depth4 gage in a common plane.

On the arm -15- of the member I3- a trammel point -17- is longitudinallymovable, the latter being of the Brown & Sharpe or any other well-knowntype. The flat face -16- of the arm 15- serves to maintain the trammelpoint in the plane of the member -13 and the rod -2.

Then assembled as shown in full lines in Fig. 1 the instrument may beused to measure the diameter of shafts, etc., or the thickness of a bodyfrom the smallest dimension up to the maximum distance attainablebetween the end of the rod Q- and the free end or point of the trammelpoint. Primarily t-he trammel point -l7# must be adjusted to a givenposition on the arm -15- To accomplish this the rotating member engagingthe rod -2- is turned to register O on the depth gage scale. Then saidrod -2- is moved longitudinally a distance exceeding the diameter orthickness to be measured and so that an annular recess -3- thereof isengaged. Then the trammel point is moved until the free end or pointthereof is in contact with the end of the rod -2- and is there secured.The rod -2- is then moved back so that the distance between the endthereof and the point of the trammel is greater than the diameter orthickness to be measured and always of course so that one of the annulargrooves therein is engaged. By then turning the engaging member the saidrod -2- is moved until the distance between the opposing points accordswith the diameter or thickness of the interposed body. The distancewhich the rod -2- was projected below the lower face of base or foot M1to primarily adjust the position of th`e trammel point, less one-halfinch (allowed for travel of the rod -2-) constitutes the basicmeasurement to which is added the fractional part of a half inchregistered on the depth gage scale after final adjustment of the rod v2-and trammel point to confine the interposed body therebetween. In otherwords, if a shaft measuring between two and two and onehalf inches is tobe measured, the rod .-2- is projected two and one-half inches below theplane face of the base or foot 1 Then the trammel point is adjusted tocontact therewith and the rod then returned to its original position,thus leaving the distance between opposing points two and one-halfinches. The rod -2- is then projected by revolving the engaging memberVuntil the distance between opposing points equals the diameter of theshaft. By then rea ling on the graduated scale on the standard, thefractional part of the inch is read and this added to two inches is thediameter of the shaft.

By turning the trammel point and the depth gage each one-hundred-eiglitydegrees as shown in dotted lilies in Fig. -lthe device may be used tomeasure large inside vdimensions as of openings or recesses.

By removing the member -G- from engagement with the base or foot -lthedepth gage is used independently.

The use of the device for measuring the dimensions of openings isrelatively very limited.

In Fig. -2- I have illustrated amodiied form of construction in which anextension member -18- is mounted upon the free end portion of the member-6-, the said member -IS- having a transverse opening therein for thepassage of the shank w19- of an anvil -20-, said shank -l9 beingprovided with a flat face similarly to the arm -15- of the member I3-and for the same purpose. The point Qlof the anvil opposes the rod 2 andcoacts with the latter to measure diameters and thicknesses, but is notadapted for the measurement of openings or recesses.

My said device enables accurate measurements to be made and serves toobviatc the use of a large number and variety of mierometers andattachments therefor.

I claim as my invention:

l. The combination with a depth-gage of a jointed L-shaped memberremovably secured at the free end of one arm to the base of said gage,said arm being separable between its ends and the parts thereofpivotally movable with relation to each other, means for holding saidparts against relative movement, the other arm of said member beingadapted to be held parallel with the rod of said depth gage, and atrammel point slidable on said last-named arm and having its free enddisposed in axial alinement with said rod.

2. The combination with a depth-gage of a jointed L-shaped memberremovably seA cured atthe free end of one arm to the base of said gage,said arm being separable bctween its ends and the parts thereofpivotally movable with relation to each other, means for holding saidparts against relative movement, the other arm of said ointed `memberbeing adapted to be held parallel with the rod of said depth gage, amember slidable on said last-named arm, and a point member removably andadjustably mounted in said last named member and adapted. to be adjustedthereon to bring the free end thereof into axial alinement with saidrod.

3. The combination with a depth gage, of a jointed member removablysecured to the base thereof, the parts of said jointed memposed in axialalinement with the rod of 10 ber being separable and rotatablerelatively said depth-gage.

to each other, and a member adjustably en- In testimony whereof I havesigned my gaged with said jointed member and having name in the presenceof two subscribing Wita point-portion disposed parallel with the nesses.

axis of said jointed member, said last-named HENRY SPAHN. member beingmovable toward and away Witnesses: from said jointed member, the freeend of W. W. JOHNSON,

said point-portion being adapted to be dis- A. FRANK PHJLEPEAU.

